suzerain: #3082 dynamic eps based on mean_rho

Added dynamic epsilon cutoff values that scale with the mean
density.  Magnitudes set as described in the comments with
the intent being to not perturb the cases that Victor has
used for parameter tuning/smoke testing.

git-svn-id: https://svn.ices.utexas.edu/repos/pecos/suzerain/trunk@44526 0bd85f0b-c151-43b9-a1e9-27231104551f